Help Topic: Editing Your Post
As described in this Member Agreement topic on "Editing Guidelines," for one hour after you post something an "Edit" button will appear at the bottom of your post:
Clicking it allows you to edit your post so that you can correct typos, formatting errors, and the like.
After the hour expires, the "Edit" button is no longer available and your post is considered to have entered the permanent record. After the editing window expires, posts can only be edited by eG Forums hosts or managers to conform to the eGullet Society Member Agreement, and only with your explicit permission to do so.